The present invention provides a most suitable prodrug of a cinnamide compound. The prodrug is represented by Formula (I) ##STR00001## wherein R.sub.a and R.sub.b each denote a C1-6 alkyl group or the like; X.sub.a denotes a methoxy group or a fluorine atom; Y denotes a phosphono group or the like; and A denotes a cyclic lactam derivative.

Claim:

The invention claimed is:

1. A compound represented by Formula (I) or its pharmacologically acceptable salt: ##STR00044## wherein R.sub.a and R.sub.b are the same or different and each denote ahydrogen atom or a C1-6 alkyl group; X.sub.a denotes a methoxy group or a fluorine atom; Y denotes --CO--(O).sub.n--R.sub.c.M.sub.a.sup.-, wherein R.sub.c denotes a C1-6 alkyl group, 6- to 14-membered aromatic hydrocarbon ring group, 5- to 14-memberedaromatic heterocyclic group, 6- to 14-membered non-aromatic hydrocarbon ring group, or 5- to 14-membered non-aromatic heterocyclic group, which may be substituted with the same or different 1 to 5 substituents selected from Substituent Group A1; n is 0or 1; and M.sub.a.sup.- denotes an anion, --P(.dbd.O) (OR.sub.d).sub.2.M.sub.a.sup.-, wherein R.sub.d denotes a C1-6 alkyl group which may be substituted with the same or different 1 to 3 substituents selected from Substituent Group A2, andM.sub.a.sup.- denotes an anion, --P(.dbd.O) (OH).sub.2.M.sub.a.sup.-, wherein M.sub.a.sup.- denotes an anion, --P(.dbd.O) (--O.sup.-) (OH), or --P(.dbd.O)(--O.sup.-) (--O.sup.-.M.sub.b.sup.+), wherein M.sub.b.sup.+ denotes a cation; A is represented byFormula (A-1): ##STR00045## wherein (a) R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are the same or different and each denote a hydrogen atom or a C1-6 alkyl group, X.sub.1 denotes a C1-6 alkylene group which may be substituted with 1 to 3 hydroxy or C1-6alkyl groups which may be substituted with 1 to 3 hydroxy groups, X.sub.2 denotes an oxygen atom or a methylene group which may be substituted with 1 or 2 C1-6 alkyl groups, and Ar.sub.1 denotes --X.sub.1-a--Ar.sub.1-a, wherein Ar.sub.1-a denotes a 6- to14-membered aromatic hydrocarbon ring or 5- to 14-membered aromatic heterocyclic group, which may be substituted with the same or different 1 to 3 substituents selected from Substituent Group A2, and X.sub.1-a denotes a single bond or an oxygen atom; or(b) R.sup.1, R.sup.2, R.sup.3, R.sup.4, and X.sub.2 are the same as defined above, and Ar.sub.1-X.sub.1-- denotes a C3-8 cycloalkyl group which has a methylene group which may be substituted with an oxygen atom condensed with a benzene ring which may besubstituted with the same or different 1 to 3 substituents selected from Substituent Group A2, or A is represented by Formula (A-2): ##STR00046## wherein denotes a single bond or a double bond; Ar.sub.2 denotes a 6- to 14-membered aromatic hydrocarbonring or 5- to 14-membered aromatic heterocyclic group, which may be substituted with the same or different 1 to 3 substituents selected from Substituent Group A2; R.sup.5 and R.sup.6 are the same or different and each denote a substituent selected fromSubstituent Group A2; Z.sub.1 and Z.sub.2 are the same or different and each denote a methylene or vinylene group, which may be substituted with the same or different 1 or 2 substituents selected from Substituent Group A2, an oxygen atom, or an iminogroup which may be substituted with a C1-6 alkyl or C1-6 acyl group; and p, q, and r are the same or different and each denote an integer of 0 to 2, wherein Substituent Group A1 consists of (1) hydroxy groups, (2) cyano groups, (3) C3-8 cycloalkoxygroups, (4) C1-6 alkoxy groups which may be each substituted with 1 to 3 substituents selected from the group consisting of halogen atoms, hydroxy groups, cyano groups, C3-8 cycloalkyl groups, and C3-8 cycloalkoxy groups, (5) amino groups which may beeach substituted with 1 or 2 C1-6 alkyl groups which may be each substituted with 1 to 3 halogen atoms, (6) carbamoyl groups which may be each substituted with 1 or 2 C1-6 alkyl groups which may be each substituted with 1 to 3 halogen atoms, (7) carboxylgroups, (8) pyridinyl groups, and (9) sugar residues; and Substituent Group A2 consists of (1) halogen atoms, (2) hydroxy groups, (3) cyano groups, (4) C3-8 cycloalkyl groups, (5) C3-8 cycloalkoxy groups, (6) C1-6 alkyl groups which may be eachsubstituted with 1 to 3 substituents selected from the group consisting of halogen atoms, hydroxy groups, cyano groups, C3-8 cycloalkyl groups, C1-6 alkoxy groups, and C3-8 cycloalkoxy groups, (7) C1-6 alkoxy groups which may be each substituted with 1to 3 substituents selected from the group consisting of halogen atoms, hydroxy groups, cyano groups, C3-8 cycloalkyl groups, and C3-8 cycloalkoxy groups, (8) amino groups which may be each substituted with 1 or 2 C1-6 alkyl groups which may be eachsubstituted with 1 to 3 halogen atoms, and (9) carbamoyl groups which may be each substituted with 1 or 2 C1-6 alkyl groups which may be each substituted with 1 to 3 halogen atoms.

2. The compound or its pharmacologically acceptable salt according to claim 1, wherein X.sub.a denotes a methoxy group.

3. The compound or its pharmacologically acceptable salt according to claim 1, wherein X.sub.a denotes a fluorine atom.

5. The compound or its pharmacologically acceptable salt according to claim 1, wherein Ar.sub.1 denotes a 6- to 14-membered aromatic hydrocarbon ring or 5- to 14-membered aromatic heterocyclic group which may be substituted with the same ordifferent 1 to 3 substituents selected from the aforementioned Substituent Group A2.

6. The compound or its pharmacologically acceptable salt according to claim 1, wherein Ar.sub.1 denotes a phenyl or pyridinyl group, which may be substituted with the same or different 1 to 3 substituents selected from the aforementionedSubstituent Group A2.

7. The compound or its pharmacologically acceptable salt according to claim 1, wherein Ar.sub.1 denotes a phenyl group, a pyridinyl group, or a phenyl or pyridinyl group which has been substituted with 1 to 3 halogen atoms.

9. The compound or its pharmacologically acceptable salt according to claim 1, wherein X.sub.2 denotes a methylene group.

10. The compound or its pharmacologically acceptable salt according to claim 1, wherein X.sub.2 denotes an oxygen atom.

11. The compound or its pharmacologically acceptable salt according to claim 1, wherein Z.sub.1 and Z.sub.2 are the same or different and each denote an oxygen atom or a methylene group which may be substituted with 1 or 2 of C1-6 alkyl groups,halogen atoms, and hydroxy groups; and R.sup.5 and R.sup.6 are the same or different and each denote a C1-6 alkyl group, a halogen atom, or a hydrogen atom.

12. The compound or its pharmacologically acceptable salt according to claim 11, wherein Z.sub.1 and Z.sub.2 are the same or different and each denote a methylene group which may be substituted with 1 or 2 of C1-6 alkyl groups, halogen atoms,and hydroxy groups; and p, q, and r are each 1.

13. The compound or its pharmacologically acceptable salt according to claim 11, wherein Z.sub.1 and Z.sub.2 are the same or different and each denote a methylene group which may be substituted with 1 or 2 of C1-6 alkyl groups, halogen atoms,and hydroxy groups; p and q are each 1; and r is 0.

14. The compound or its pharmacologically acceptable salt according to claim 11, wherein Z.sub.1 denotes a methylene group which may be substituted with 1 or 2 of C1-6 alkyl groups, halogen atoms, and hydroxy groups; Z.sub.2 denotes an oxygenatom; and p, q, and r are each 1.

15. The compound or its pharmacologically acceptable salt according to claim 11, wherein Z.sub.1 denotes an oxygen atom; Z.sub.2 denotes a methylene group which may be substituted with 1 or 2 of C1-6 alkyl groups, halogen atoms, and hydroxygroups; and p, q, and r are each 1.

16. The compound or its pharmacologically acceptable salt according to claim 11, in which Z.sub.1 denotes an oxygen atom; Z.sub.2 denotes an oxygen atom; and p, q, and r are each 1.

17. The compound or its pharmacologically acceptable salt according to claim 11, wherein Ar.sub.2 denotes a phenyl group which has been substituted with 1 to 3 halogen atoms.

18. The compound or its pharmacologically acceptable salt according to claim 11, wherein Ar.sub.2 denotes a phenyl group which has been substituted with 2 or 3 halogen atoms.

19. The compound or its pharmacologically acceptable salt according to claim 1, wherein R.sup.5 and R.sup.6 are the same or different and each denote 1 or 2 of C1-6 alkyl groups, halogen atoms, and hydrogen atoms.